Nanoscale Vectorial Electric and Magnetic Field Measurement

In technology, old or new, from basic imaging through
a camera
lens to advanced applications such as fluorescence microscopy and
optical lithography, there are countless examples that would be inconceivable
without the utilization of focused light. As technology evolves, the
demands on spatially confined light fields grow but so do the challenges
of accurately characterizing these complex fields. This study introduces
a technique to measure the full vectorial nature of light, reaching
sub/wavelength spatial resolution while capturing the 3D amplitude
and phase for both electric and magnetic fields. This is achieved
based on a polarization-resolved far-field analysis of light scattered
by a single spherical nanoparticle acting as a local probe. For experimental
verification, the method is applied to tightly focused light fields
under various input scenarios. Offering high resolution, precision,
and flexibility, this technique shows great promise for both fundamental
research and applications in technologies relying on highly localized
light fields.